Very recently, molecular diagnostics has increasingly gained in importance. It has found an entry into the clinical diagnosis of diseases (inter alia detection of infectious pathogens, detection of mutations of the genome, detection of diseased cells and identification of risk factors for predisposition to a disease).
In particular, through the determination of gene expression in tissues, nucleic acid analysis opens up very promising new possibilities in the study and diagnosis of disease.
Nucleic acids of interest to be detected include genomic DNA, expressed mRNA and other RNAs such as MicroRNAs (abbreviated miRNAs). MiRNAs are a new class of small RNAs with various biological functions (A. Keller et al., Nat Methods. 2011 8(10):841-3). They are short (average of 20-24 nucleotide) ribonucleic acid (RNA) molecules found in eukaryotic cells. Several hundred different species of microRNAs (i.e. several hundred different sequences) have been identified in mammals. They are important for post-transcriptional gene-regulation and bind to complementary sequences on target messenger RNA transcripts (mRNAs), which can lead to translational repression or target degradation and gene silencing. As such they can also be used as biologic markers for research, diagnosis and therapy purposes.